Ocular counterrolling: an indicator of bilateral vestibulopathy

The ocular counterrolling can be static or dynamic. The purpose of this work is to connect the clinical absence of dynamic ocular counterrolling with bilateral caloric paresis. A prospective study on 216 patients in whom the absence of dynamic ocular counterrolling was tested and standard caloric test was performed. The cut-off value for bilateral caloric paresis is an absolute reflectivity of 10 in nystagmic frequency and 8 in slow phase velocity. The adequate contingency tables were constructed and tests of Chi-squared calculated. Sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, and area under receiver operating characteristic (ROC) curve were also calculated. Using the reflectivity according to the nystagmic frequency, we obtained P = 0.000 for Chi-squared, area under ROC curve was 0.832 and positive likelihood ratio 11.47. For slow-phase velocity, the results were P = 0.000, area ROC of 0.735 and positive likelihood ratio 9.43. There is a statistically significant connection between the clinical absence of dynamic ocular counterrolling and bilateral caloric paresis, with a strong diagnostic power. The mechanisms by which this phenomenon can be attributed to canalicular damage instead of otolithic damage are discussed.